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Version: v23.0

Upgrade DxEnterprise Containers in Kubernetes

Introduction​

This guide describes how to update a DxEnterprise container deployed in a Kubernetes statefulset. Using this guide, you will select an update strategy that best fits your needs, and then follow the steps to update the DxEnterprise container images.

Prerequisites​

info

All command examples below use the statefulset name of dxemssql with 3 pods joined to an availability group named dxemssql-0 (primary), dxemssql-1 (secondary) and dxemssql-2 (secondary).

Update Strategies​

There are 2 update strategies to choose from when performing pod updates in Kubernetes:

  • OnDelete

    When a StatefulSet's .spec.updateStrategy.type is set to OnDelete, the StatefulSet controller will not automatically update the Pods in a StatefulSet. Users must manually delete Pods to cause the controller to create new Pods that reflect modifications made to a StatefulSet's .spec.template.

  • RollingUpdate

    The RollingUpdate update strategy implements automated, rolling updates for the Pods in a StatefulSet. This is the default update strategy.

OnDelete​

One advantage of the OnDelete update strategy is that updates can be staged ahead of time, but aren't deployed until the pods are deleted, one-at-a-time at the preferred time and in the preferred order.

  1. To prepare the upgrade process, use the command below to change the update strategy on the statefulset deployment from RollingUpdate (default) to OnDelete.

    kubectl patch statefulset dxemssql -p '{"spec":{"updateStrategy":{"type":"OnDelete","rollingUpdate":null}}}'

  2. Verify that Update Strategy has been changed to OnDelete.

    kubectl describe statefulset dxemssql

  3. Update the statefulset to use the latest DxEnterprise image.

    info

    Running the below command will not trigger the upgrade. The upgrade will occur only after deleting the pod.

    kubectl set image statefulset dxemssql docker.io/dh2i/dxe:23.0.256.0-rhel8-arm64
    tip

    Any image that uses the latest tag will automatically be upgraded whenever a new image is posted to the repository. If a specific OS, version or architecture is required, then supply that specific container tag.

  4. Verify that the dxe container image has been updated to the desired container tag.

    kubectl describe statefulset dxemssql

  5. Delete each secondary pod individually. Kubernetes will automatically recreate the pods in the statefulset using the updated image tags. Once the pod has been upgraded and rejoined the availability group, then delete the next secondary pod, and so on, until all of the secondary pods have been upgraded.

    kubectl delete pod dxemssql-<pod_number>

  6. Delete the final pod to complete the upgrade. This command will force the availability group primary replica role to move to one of the secondary pods.

    kubectl delete pod dxemssql-0

RollingUpdate​

Using the RollingUpdate option allows a phased roll out of pod updates, with the highest ordinal value pod being updated first and the lowest ordinal value pod being updated last. One advantage of this option is that accidental deletion of a pod will not cause an unexpected update to occur.

  1. To prepare the update process, first verify what the current update strategy is. The value of .spec.updateStrategy.type should be set to RollingUpdate and .spec.updateStrategy.rollingUpdate.partition should be set to 0.

    kubectl describe statefulset dxemssql

  2. Update the statefulset to set the .spec.updateStrategy.partition to 2. This will ensure that only pods with an ordinal value greater than or equal to 2 are updated (dxemssql-2).

    kubectl patch statefulset dxemssql -p '{"spec":{"updateStrategy":{"type":"RollingUpdate","rollingUpdate":{"partition":2}}}}'

  3. Push the update. During the update only pod(s) with an ordinal value greater than or equal to the partition number will be updated. Pods with an ordinal value less than the partition number will remain running and unaffected.

    caution

    This command will trigger the RollingUpdate strategy to begin. This command should only be run at the time that you want the update to occur.

    kubectl set image statefulset dxemssql dh2i/dxe:23.0.256.0-rhel8-arm64
    tip

    Any image that uses the latest tag will automatically be upgraded whenever a new image is posted to the repository. If a specific OS, version or architecture is required, then supply that specific container tag.

  4. Repeat the command in step 2, reducing the partition number each time until the partition number is equal to 0. As the partition number is reduced, all pods with an ordinal value greater than or equal to the partition number will automatically be updated.

References​